CVE-2025-66176 Overview
CVE-2025-66176 is a stack overflow vulnerability affecting the device Search and Discovery feature of Hikvision Access Control Products. This vulnerability allows an attacker on the same local area network (LAN) to cause the affected device to malfunction by sending specially crafted packets to an unpatched device. The vulnerability is classified under CWE-121 (Stack-based Buffer Overflow).
Critical Impact
An adjacent network attacker can exploit this vulnerability to cause device malfunction, potentially leading to complete compromise of confidentiality, integrity, and availability of the affected Hikvision access control systems.
Affected Products
- Hikvision Access Control Products (Search and Discovery feature)
- Devices with unpatched firmware versions
- Network-connected access control devices on shared LAN segments
Discovery Timeline
- 2026-01-13 - CVE CVE-2025-66176 published to NVD
- 2026-01-13 - Last updated in NVD database
Technical Details for CVE-2025-66176
Vulnerability Analysis
The vulnerability resides in the Search and Discovery feature of Hikvision Access Control Products. This feature is commonly used for device discovery and configuration on local networks. The stack overflow condition occurs when the device processes specially crafted network packets, allowing an attacker to overwrite critical stack memory regions.
Stack-based buffer overflows like this one (CWE-121) are particularly dangerous as they can allow attackers to overwrite return addresses and potentially execute arbitrary code or cause denial of service conditions. In this case, the primary impact described is device malfunction, which suggests the vulnerability can reliably crash or destabilize the affected devices.
The adjacent network attack vector means the attacker must be on the same LAN segment as the target device, which provides some protection against remote internet-based attacks but still presents significant risk in enterprise and shared network environments.
Root Cause
The root cause is a stack-based buffer overflow (CWE-121) in the device Search and Discovery feature. This occurs when the software writes data beyond the boundaries of a stack-allocated buffer while processing network discovery packets. The lack of proper bounds checking on input data allows oversized or malformed packets to corrupt the stack memory structure.
Attack Vector
The attack vector is via the adjacent network, requiring the attacker to be on the same local area network as the vulnerable Hikvision access control device. The attacker can exploit this vulnerability by:
- Gaining access to the same LAN segment as the target device
- Identifying vulnerable Hikvision access control devices using the Search and Discovery feature
- Sending specially crafted packets designed to trigger the stack overflow condition
- Causing the device to malfunction or crash
The vulnerability requires no authentication and no user interaction, making it trivially exploitable once network access is obtained. For detailed technical information, refer to the Hikvision Security Advisory.
Detection Methods for CVE-2025-66176
Indicators of Compromise
- Unexpected device reboots or crashes of Hikvision access control equipment
- Anomalous network traffic patterns targeting device discovery ports
- Malformed or oversized packets in network captures targeting Hikvision devices
- Access control devices becoming unresponsive or entering error states
Detection Strategies
- Monitor network traffic for unusual discovery protocol activity on LAN segments containing Hikvision devices
- Implement network intrusion detection rules to identify oversized or malformed discovery packets
- Deploy endpoint detection on network segments to identify exploitation attempts
- Enable logging on Hikvision devices to capture crash events and abnormal behavior
Monitoring Recommendations
- Segment Hikvision access control devices onto dedicated VLANs with restricted access
- Implement network traffic analysis on segments containing vulnerable devices
- Monitor device health status through centralized management platforms
- Configure alerting for device offline or crash events that may indicate exploitation
How to Mitigate CVE-2025-66176
Immediate Actions Required
- Review the Hikvision Security Advisory for specific patch information
- Identify all Hikvision access control devices on the network
- Isolate vulnerable devices on dedicated network segments with restricted access
- Apply available firmware updates from Hikvision as soon as possible
Patch Information
Hikvision has published a security advisory addressing this vulnerability. Administrators should consult the Hikvision Security Advisory to identify specific affected product models and firmware versions, and obtain the appropriate security patches for their deployed devices.
Workarounds
- Implement network segmentation to isolate Hikvision access control devices from general network traffic
- Restrict access to the LAN segments containing vulnerable devices using firewall rules and VLANs
- Disable the Search and Discovery feature if not required for operational purposes
- Monitor network traffic for suspicious activity targeting device discovery protocols
# Network segmentation example - restrict access to device VLAN
# Example iptables rules to limit access to Hikvision device segment (adjust as needed)
iptables -A FORWARD -i eth0 -o eth1 -d 192.168.10.0/24 -j DROP
iptables -A FORWARD -i eth1 -o eth0 -s 192.168.10.0/24 -m state --state ESTABLISHED,RELATED -j ACCEPT
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
